In an LTE (Long Term Evolution-Advanced, long term evolution)—Advanced (LTE-A for short) system, a relay (Relay) is introduced between an eNodeB and a cell, so as to implement the expansion of cell coverage, improve throughput of a cell edge and enhance data transmission capability of a hot pot, thereby enriching the user experience of the LTE/LTE-A system.
In first several OFDM (Orthogonal Frequency Division Multiplexing, orthogonal frequency division multiplexing) symbols of an MBSFN (Multicast Broadcast Single Frequency Network, multicast broadcast single frequency network) subframe, the eNodeB sends a downlink control channel (such as a PCFICH (Physical Control Format Indicator Channel, physical control format indicator channel), a PDCCH (Physical Downlink Control Channel, physical downlink control channel), or a PHICH (Physical Hybrid ARQ Indicator Channel, physical HARQ indicator channel) to a UE, and in subsequent several OFDM symbols, the eNodeB sends control information to a relay in a predefined common resource region, where the common region is formed by several resource elements in multiple PRB (Physical Resource Blocks, physical resource blocks). The PRB region stores time-frequency resources used by all relays, and the eNodeB maps data information that is sent to the UE and the relay to respective positions.
In a mobile communication system, because a radio channel between different relays and the eNodeB vary greatly, in a position of an optimum common resource region that is compromised among all relays and occupies limited time-frequency resources, reception of each relay control signal cannot be optimized, which easily results in small coverage of an eNodeB cell, and therefore, relays at edges of the eNodeB cell or under other adverse channel conditions cannot be effectively supported. Furthermore, because all relays need to judge, through blind detection in the common region, whether any control information is sent to the relays, the calculation burden and complexity are increased.